Rotatable drawing board and attached straightedge



Feb. 2, 1932. A. LA FRANCE 1,843,824

ROTATABLE DRAWING BOARD AND ATTACHED STRAIGHTEDGE Filed Oct. 23, 1929 3Sheets-Sheet 1 sllllllllllu lllllll WM Qa/ww A TTORNEY.

A. A FRANCE 1,843,824

ROTATABLE DRAWING BOARD AND ATTACHED STRAIGHTEDGE Feb. 2, 1932.

Filed Oct. 23, 1929 3 Sheets-Sheet l.:: @hipo INVENToR. f77/fred a Fancemgm ATTORNEY.

INVENTOR.

ATTORNEY.

3 Sheets-Sheet 3 A. LA FRANCE Filed oct. 2s, 1929 ROTATABLE DRAWINGBOARD AND ATTACHED STRAIGHTEDGE Feb. 2, 1932.

Patented Feb. 2, 1932 leisen PATENT OFFCE ALFRED LA FRANCE, F CENTRALFALLS, RHODE ISLAND RoTA'rAisLEnRAWING Bom AND AT'rAeHED STRAIGHTEDGE.Application led October" 23, 1929; rSerial No. 401,760.

This invention relates to a .draf/ ting device, the Ageneral object ofthe invention being to provide a device which will take the place vof avruimt-rer of the instrumentsnow tt? used, so'that it isnot necessary topick up or lay aside `such instruments, and it eliminates the use oftriangles.

`A further object of the invention is to provide means whereby al1.lines are drawn 10 in a-lhorizontal position anda .line can be drawnvatiany-'angle and the Jull Width of the board.l

This invention also consists in certain other Afea-tures ofconstruct-iemand in the 'combi- 35 nation and arrangementfof the severalparts, to gbe hereinatfter :fully described, illustrated in theaccompanying drawings .and specifically pointedoutin the appendedclaims.

v-In describing the invention detail, reference Will be haizlitotheacconrpanying'drawings 'Whereinlilre characters denotelliike orcorresponding parts :throughout the Asearer-al views,'andiinvvhich:-

Figure f1 V'isla 'pl-an View of fthe device.

` Z5 Figure 2 is an edge View. i Y

Figure'i'Svis fafsimilarview, buttaiken at right angles to Figure 2. y

Fligumef'isasection on line -4-4 01'?V 'Fig- 11ml, i 'fsf'. il I Figure5 -a section :onl fline 5.-5 Iof Figure 1. i l

Figure 6-` is a section online 6-6 of Figura''.. Y

Figureff? fis'. a plan iview', 'partly in section, fshowing'the'nieansfor controlling' the movevment-.of fthe fturntable.

/ Figua'e lis aftop plan view with the square strip. removed and-showingthe -means for adjusting thesquare over :the board.

Figure 9 is a section on line 9-9 of Figure'fS. l

Figure 1i0is1asection on line 10-10 of Figure 9. r

In these views, lthe numeral 1 indicates the ysupporting ,-mem'ber towhich the turntable 2-is 4pivoted at itscenter, :as shownat 3, the upperpartv of vthe .supporting member being recessed tax-receive the table sothat the table is :Hush with the .upper surface of said niem- 59 iber. Aaboard 4 is-.zremovably placed on `the table and is caused to turnVtherewith by means of the projection 5 on the table 'engagin'g a vnotch`r6 in the board. The board is of .less diameter than 'the table so.that the periphery of the table is exposed and a portion of 'theperiphery of the table is formed with the teeth 7 which formvgraduatio'ns on the table and these graduations are divided into tenthsby the vnumerals and lines 8. A bar :9 is arranged Ain a space in the-supporting member and has an arm 10 intermediate its ends which'carries a pin 11 projecting through a hole 12 in the supporting memberand adapted to engageV the teeth 7, the pin being norm-ally heldinfengagement with the teeth by the spring 13 which connects the centrallfpart of rthelbar -With fa part 'of the supporting member. One end ofthe bar 9 is pivoted -to an arm 14 arranged in an opening 15 :in thesupporting member, vand this arm is connected by a--screvv` 1'6 with anarm 17 `which operates -over Ya plate 18 on the supporting'member, saidplate having a lhole 19 therein through-which apa-rt 14 of the anni '14extends, so that thetvvov `arms are pivotally supported by the plate,and the movement `of fthe outer arm l17 will becommunicafted tothe arm14. The plate carries a fraised portion 2'() having .a vernier on itsupper Vsnrae'e :and :a "spring .plunger 21 is carried-by the vfarm 17and frictionally engages the inner :Wall of the enlargement 20 so thatthis plunger acts to hold :the arm 17 in adjusted position. The otherIend of the bar 9 Jhas a slottherein vfor receiving a headed pin22'depending from an arm 23 having a'bearin-gfpart 2.4 passing through ahole in a plate :25 carried by the supporting member and an :a'rmk26 isfastened to the bearing part and operates over the plate 25 so that byvmoving vthis arm 26, the arm 23 is -moved and this movement of the arm23 Will swing the bar I'9 outwardly against the action of its spring andthus move the pln 11 out of engagement with the toothed p0rtion of thetable so that the table is free to move. The arm 26 carries a springplunger 27 which isadapted to engage a hole 28 in the plate 25 When thearm is moved to a posit-ion to swing the bar 9outwardly, thus holdingthe bar in this position against the action of its spring 13. The arms17 and 14 act to move the bar 9 longitudinally and thus cause the pin 11to move the table a certain distance on its pivot 3 and this distancecan be accurately gauged by the von nier on the enlargement 20.

From the foregoing it Will be seen that the table can be accuratelymoved by moving the arm 17 to certain distances and by mov` ing the bar9 by the arm 26, the table Will be freed of the pin 11 so that the tablecan be turned freely to any desired position.

A guide bar 29 is supported at -one edge of the board by the projections30, this bar having a reduced lower part which is formed with the racltteeth 31 on its inner edge and a channel shaped member 32 is slidablyarranged on the bar and is formed with a casing 33 at its center. Agraduated elongated plate 34 has one end fastened to the casing by thescrews 35 and this plate 34 and the member 32 forms a T square. That endof the plate 34 which is connected With the casing forms a cover for thecasing. A pressure bar 36 is arranged in the casing and carries a roller37 at its inner end for engaging the inner edge of the bar 29 and saidbar 36 carries a spring 38 which is forced against a part of the casingby a thumb screw 39 threaded in the outer end of the member 36. Thusthis bar and its parts act to frictionally connect the casing with thebar 29, and the frietional engagement of the roller with the bar 29 canbe controlled by adjustment of the spring 38 by the screw 39. A lever 40is pivoted in the casing and has a projection 4l thereon engaging anotch in the member 36` with one end of the lever projecting outwardlyfrom the casing. Thus by pressing upon the outer end of this lever andagainst a handle 42 connected with the casing, the bar 36 is movedinwardly so as to move the roller 37 away from the bar 29 and thuspermit the member 32 to have free movement on the bar 29.

A lever 43 is nivoted in the casing between the lever 40 and the handle42 and the inner end of this lever 43 has a dog 44 pivoted thereto, withthe dog engaging the rack teeth 31. The dog 44 is frictionally connectedwith the lever 43, as shown at 45, and aspring 46 normally holds the.lever with its inner end against a Wall of the casing and the dogretracted.

A combined lever and pointer 47 is frictionally pivoted to a part of thecasing and has its pointed end passing through the casing and thispointed' end operates over a scale 48 on the member 32. The inner partof the lever carries a depending projection 49 which extends into thepath of the pawl and acts to control the movement of the pawl by thelever 43. W'hen the lever 47 is on the graduation l of the scale 48, thepaWl has but a limited movement so that when the pavvl is operated bythe lever 43, the T square is moved but one step on the bar 31, but whenthe lever 47 has its pointed end opposite the graduation 4, the T square1s moved four steps or over four teeth 31 every time the paivl is movedby the lever 43. I

Thus it will be seen that by pressing With the thumb and a finger of onehand upon the handle 42 and the lever 40, the friction bar 36 is movedto position the roller 37 out of Contact with the guide bar 29 so thatthe T square can be adjusted to any position over theY board on theturntable and by' placing the thumb and finger on the handle 42 and thelever 43 and applying pressure upon the lever 43, the T square is movedby the dog a certain distance, this distance being controlled by thepositioning of the level' 47 on the scale 48. Thus it will be seen thatI have provided a device which Will take the place of a number ofinstruments now used in drafting, with all the controls at thefingertips. ready to operate Without having to pick up 'or lay asidedifferent instruments. Thel T square will remain in a set position whenthe board is inclined and it can be adjusted to any desired position onthe board and the board can be turned to draw lines on the sheetthereon, through means of the T square, at any angle and tliefull Widthof the board. The board and the turntable can revolve in eitherdirection and it can be locked at every degree and can be shifted infractions of a degree While in locked position. The lock can be moved,to inoperative position and held there so that the board can be turnedat Will'. The member 32 has slight tilting movement on the bar 29 sothat by slight pressure upon the handle,

the square can be raised above the board so'A that it will pass overthumb tacks or the like.

While the drawings show the board on the turntable of circular shape, itwill, of course, be understood that any shape of board can be placedthereon.

It is thought from the foregoing description that the advantages andnovel features of the invention Will be readily apparent.

It is to be understood that changes may be made in the construction andin the combination and arrangement of the several parts, provided thatsuch changes fall Within the scope of the appended claims.

What I claim is 1. A drafting instrument comprising a supporting member,a turntable thereon, locking means for the same, means for adjusting thetable when in locked position, a guide bar on the. supporting means, aT-square slidably arranged on the bar, adjustable means for frictionallyholding the square against movement, a lever for moving the frictionmeans into inoperative position, said guide bar having rack teeththereon, a pawl carried by a part of the T square and engaging theteeth, a lever for operating the pawl, a second lever for controllingthe amount of movementl of the pawl by the lever.

2. A drafting instrument comprising a. supporting member, a turntablethereon, looking means for the same, means for adjusting the table whenin locked position, a guide bar on the supporting means, a T squareslidably arranged on the bar, adjustable means for frictionally holdingthe square against movement, a lever for moving the friction means intoinoperative position, said guide bar having rack teeth thereon, a pawl'carried by a part of the T square and engaging the teeth, a lever foroperating the pawl, a second lever for controlling the amount ofmovement of the paWl by the lever, a scale for facilitating thead'ustment of the control lever and means Where y the square can betilted on the guide bar to raise the same above the table.

In testimony whereof I aix my signature.

ALFRED LA FRANCE.

